Model 66 no dash locking-up due to heat expansion of Gas Ring?

[Dump1567]

I was recently watching one of the older Wilson Combat You Tube videos where Mas Ayoob was discussing his career and the duty guns he used. One Dept. he was on required to use the model 66 no dash as a duty gun. He said these guns where prone to locking-up due to heat expansion of the gas ring. And why the 66-1 moved the ring from the cylinder to the crane. And they were also prone to heating-up due to the steel they used (or something like that).

Has anyone ever experienced this?

Here's the video it comes from if anyone is interested.

https://youtu.be/yMSKDL7xOb4

 

[MontanaNerd]

I bought a brand new Model 57 .41 mag two years ago which locked-up after two cylinders.
The cylinder gap was too small and the cylinder was slightly canted, heat expansion closed the gap.
Sent it back for factory repair and it came back flawless.
Had this happen with a Taurus model 85 about 20 years ago as well.

FWIW

 

[Engine49guy]

Interesting video thanks for sharing it.
While I have two 4" LNIB early 66 no dash revolvers I never shot those because my main revolver at that time was a tuned 66-2.
The 66 no dash was introduced during the 19-3 run so is equal to it in evolution in that they both have the gas ring on the "Yoke" ( crane is a Colt term iirc).
I have heard complaints that it allowed burnt powder to get in there and bind the cylinders movement, The 19-4 and 66-1 revision came out in 1977 and relocated the gas ring from the yoke to the cylinder so that was likely the culprit and what is referred to in the video.

On a side note the discussion came up years ago, my assumption back then was that 19-3 and earlier Combat Magnums all had the gas ring on the yoke but I never removed the cylinders to compare, IIRC a fellow member
(SNW19-357 IIRC) mentioned that his early 19-3 and 19-2 had gas rings on the cylinder which led me to believe that perhaps it was moved to the yoke during the early 19-3 revision, ( my guess is perhaps it was cheaper or faster to produce that way?)
I'm embarrassed to admit that as OCD as I am things cme up and to this day I haven't gone back and started taking my 19's apart to compare gas ring locations .
This would be an interesting topic IMO to compare, if we are lucky maybe Chris will share his notes .
As an after thought since all metal expands when heated my thoughts are that the gas ring was the culprit but heat made it much worse and that after the gas ring was moved heat was not an issue.

 

[Hair Trigger]

The M66 was released in 1970. It had the same engineering design the M19-3 had, since it was the -3 that was the current M19 version in 1970. Both the M19-3 and M66 had the gas ring moved from the yoke to the cylinder in 1974 when the M66-1 and M19-4 were released. I had never heard of the gas ring causing issues with overheating and locking up as Mr. Ayoob described, and I believe it to be an isolated issue in his case. I bought a 4" M66 back in 1978 and kept it until 2005 and never had a problem with it, and I shot it during PPC matches when I first got it, so it had a lot of rounds through it.

Also, if you read an article by "The Revolver Guy" called The L Frame Story, he talks about the evolution of the L frame to solve issues with the forcing cone flat on K frame .357's. In the article he mentions that the gas ring on M19's (and M66's) was changed from the cylinder to the yoke some time around 1974-75 without an engineering change issued, kept that way for just a couple of years and then changed back, with an engineering series change. That comment is upheld by my own M19-3 I currently own, which was made in 1974 and has the gas ring on the cylinder, so it was manufactured before the gas ring was changed to the yoke. Engineering changes such as the left-hand thread on the extractor rod, and gas ring movement, pinned/non-pinned barrels, etc. were made on all models at the same times, but not all models were in the same engineering series number at that time those changes were implemented. I believe my M66 may have also had its gas ring on the cylinder, and not been one that had been made during the short-term change.

I liked the video, pretty cool how many different service guns he carried in his career, and how the attitudes and policies regarding personal carry preference was between different departments.

The Smith & Wesson L-Frame Story – RevolverGuy.Com

 

[Engine49guy]

Just read the posted link thread by " The revolver guy"
Thank you for sharing it!
That is the most thorough and concise description of Design evolution and describing the problems and solutions that followed, it all makes so much more sense now !
Gonna share that thread with all my revolver buddies today. ; )

 

[steelslaver]

The therma expainsion rat of 400 series stainless is 10.1x10 to the 4th between 0 and 316C (32-600f) while 4140 is 24.7x10 to the 4th between 0 and 205C (32-401f) so a blue gun is more apt to expand to the point of lock up than a stainless one

Steels average expansion rate is 0.0000072 inches per degree Fahrenheit.

Here is a hand dandy thermal expansion calculator
Thermal Expansion Calculator | Good Calculators

using it

a 2" long steel cylinder would gain .00432 with a 300f rise in temp, but so would the frame also increase in length

Fahrenheit.

a 2" long stainless steel cylinder would gain . 0033 with a 300f rise in temp, but so would the frame also increase in length
About 1/4 less than the steel cylinder.

As the cylinder and the barrel would probably heat faster than the frame and yoke, I guess it could happen with a real tight gun. The yoke tube itself would be a bit behind the cylinder, as far as heating speed goes, but the cylinders surface would dump heat. I can't imagine the tube and the cylinders center hole are would get very far apart as far as temps go.

But. less than .001 endshake could become a problem about the time you could no longer touch the cylinder with your bare hands without blistering it

 

[SS336]

The therma expainsion rat of 400 series stainless is 10.1x10 to the 4th between 0 and 316C (32-600f) while 4140 is 24.7x10 to the 4th between 0 and 205C (32-401f) so a blue gun is more apt to expand to the point of lock up than a stainless one

Steels average expansion rate is 0.0000072 inches per degree Fahrenheit.

Here is a hand dandy thermal expansion calculator
Thermal Expansion Calculator | Good Calculators

using it

a 2" long steel cylinder would gain .00432 with a 300f rise in temp, but so would the frame also increase in length

Fahrenheit.

a 2" long stainless steel cylinder would gain . 0033 with a 300f rise in temp, but so would the frame also increase in length

a 2" long steel cylinder would gain .00432 with a 300f rise in temp. About 1/4 less than the steel cylinder.

As the cylinder and the barrel would probably heat faster than the frame and yoke, I guess it could happen with a real tight gun. The yoke tube itself would be a bit behind the cylinder, as far as heating speed goes, but the cylinders surface would dump heat. I can't imagine the tube and the cylinders center hole are would get very far apart as far as temps go.

But. less than .001 endshake could become a problem about the time you could no longer touch the cylinder with your bare hands without blistering it

I love it when you talk technical.
I think steelsaver just put another internet rumor to bed.

 

[Hair Trigger]

I think if any gun locks up due to thermal expansion, it either got waaaaay to hot (like a machine gun barrel/action), or it had an improper/insufficient clearance somewhere. In the case of Mr. Ayoob's M66, if it was the gas ring, it was most likely gummed up with burned powder residue. When the ring was changed from the cylinder to the yoke it was in response to fouling of the cylinder axle, causing it to be difficult to turn. It was discovered after moving it that the fouling issues were worse with the gas ring on the yoke, so it was moved back to the cylinder.

 

[CH4]

I have a 2.5” 66-1 that will lock up after shooting a few cylinders of magnums. Works fine after it cools down.

 

[Dvus]

I've had four M66 revolvers, two with the stainless sights and two later ones with the black sights. Have had no issues with any of them, and I shoot them alot.

 

[Dump1567]

Well, the reason for this question was a local shop had a 66 for sale I was interested in. I wasn't sure if I wanted a 66 no dash due to the issue Mas described.

I went back to the shop and checked it out. It turns out its a 1980 66-1. So that allegedly takes care of the heating-up and gas issue. But reading Revolver Guys assessment, the changeover thinned the forcing cone even more. Making it more prone to the forcing cone cracking using hot loads.

I picked it up anyway. I don't really plan on putting much, if any .357 mag through it. It even had my preferred carry grips.

 

[SG-688]

Ayoob wrote about the gas ring problem in the January/February, 1979 issue of American Handgunner and tangentially to the test of the Security Industries .357 in the first issue of American Handgunner in September, 1976.

My understanding is not only the expansion of the gas ring but also movement of the gas ring in the cylinder. Ayoob stated it could also happen with the blue steel revolvers. So the final fix after the gas ring went to the yoke and then back to the cylinder was to somehow more firmly secure the gas ring in the cylinder. S&W wouldn't say.

A big kicker from the 1979 article was that 66-1 and 66 no-dash revolvers were observed both ways. 3 ways if considering that 66 no-dash revolvers might have the improved gas ring. The dash number was not dispositive.

My 1978 serial number 66-1 has the gas ring in the cylinder.

 

[Jeppo]

Years ago, I bought a used 66-1. I emailed a friend a photo of the gun and asked how he thought I’d done. He saw something in the photo (must have magnified it) that I never noticed even having it in my hand.

He guessed it had become overheated with many hot loads, locked up and the shooter had tried to pry the cylinder open with something like a small screwdriver.

I always wondered how he had that level of wisdom. Now I know, 18DAI had obviously read Mas’s article. RIP my friend.

 

[Hair Trigger]

Well, the reason for this question was a local shop had a 66 for sale I was interested in. I wasn't sure if I wanted a 66 no dash due to the issue Mas described.

I went back to the shop and checked it out. It turns out its a 1980 66-1. So that allegedly takes care of the heating-up and gas issue. But reading Revolver Guys assessment, the changeover thinned the forcing cone even more. Making it more prone to the forcing cone cracking using hot loads.

I picked it up anyway. I don't really plan on putting much, if any .357 mag through it. It even had my preferred carry grips.

I have a M66-1 snubby and shoot 158 grain magnum loads in it, as I practice with what I carry and load. Granted, I've downloaded them to about 1200 fps which is about 225 fps lower than a factory load. Stay away from hot loads, stay away from lightweight bullets (no 110 or 125's) and you should be okay. Heck, .38+P are great loads for the K frames, whether a magnum or not.

 

[Engine49guy]

Interesting video thanks for sharing it.
While I have two 4" LNIB early 66 no dash revolvers I never shot those because my main revolver at that time was a tuned 66-2.
The 66 no dash was introduced during the 19-3 run so is equal to it in evolution in that they both have the gas ring on the "Yoke" ( crane is a Colt term iirc).
I have heard complaints that it allowed burnt powder to get in there and bind the cylinders movement, The 19-4 and 66-1 revision came out in 1977 and relocated the gas ring from the yoke to the cylinder so that was likely the culprit and what is referred to in the video.

On a side note the discussion came up years ago, my assumption back then was that 19-3 and earlier Combat Magnums all had the gas ring on the yoke but I never removed the cylinders to compare, IIRC a fellow member
(SNW19-357 IIRC) mentioned that his early 19-3 and 19-2 had gas rings on the cylinder which led me to believe that perhaps it was moved to the yoke during the early 19-3 revision, ( my guess is perhaps it was cheaper or faster to produce that way?)
I'm embarrassed to admit that as OCD as I am things cme up and to this day I haven't gone back and started taking my 19's apart to compare gas ring locations .
This would be an interesting topic IMO to compare, if we are lucky maybe Chris will share his notes .
As an after thought since all metal expands when heated my thoughts are that the gas ring was the culprit but heat made it much worse and that after the gas ring was moved heat was not an issue.

I recently had a chance to dig into this topic deeper, all my k frames have the gas ring on the cylinder until late 1975 so perhaps an 18 month window or so where k frames had the gas ring on the yoke.

 

[shawn mccarver]

I was recently watching one of the older Wilson Combat You Tube videos where Mas Ayoob was discussing his career and the duty guns he used. One Dept. he was on required to use the model 66 no dash as a duty gun. He said these guns where prone to locking-up due to heat expansion of the gas ring. And why the 66-1 moved the ring from the cylinder to the crane. And they were also prone to heating-up due to the steel they used (or something like that).

Has anyone ever experienced this?

Here's the video it comes from if anyone is interested.

I have never experienced it, but it was a well known issue at the time, and several agencies traded up to 66-1 or the equivalent 19, the 19-4, due to the problem.

 

[Greyman50]

Shot my 5” 27-2 yesterday until it was “hot” according to one of range owners. Very nice guys and have good little gun shop. Have never had any revolver lock up. Would guess that a through cleaning which includes disassembly of cylinder prevents such? Bought 3 S&Ws in last 2 weeks and all were absolutely filthy nasty and got the Kroil treatment then brake cleaner then Hoppes #9 treatment. Only the 67 will get shot as the other two are 100+ years old and have newer versions.